Vortioxetine-induced collagenous colitis: A rare case report

Vortioxetine is a newly approved antidepressant of the Serotonin Modulator and Stimulator family. Among its adverse events are nausea, headache, dizziness and increased risk of bleeding. It is not known to cause diarrhea or symptoms of colitis. However, in this article, a rare case of vortioxetine-induced microscopic colitis is presented. The patient is a 28-year-old female, previously healthy, who was recently diagnosed with major depressive disorder (MDD) and was started on vortioxetine 5 mg, once daily, which was gradually increased to 10 mg, once daily (OD). She soon complained of chronic watery, non-bloody diarrhea that was more severe with higher dosage of vortioxetine and improved only when the dose was reduced. Extensive work-up ruled out infectious and malabsorptive etiologies. No macroscopic changes were seen on colonoscopy, only thickening of the sub-epithelial collagen band was evident on histology which is compatible with microscopic colitis-collagenous type. Although collagenous colitis is not a known side effect of vortioxetine, physicians should pay attention to the signs and symptoms of this conditions and should stop it immediately if such case is suspected. More research and investigations are needed to study the pathophysiology of microscopic colitis and the role of vortioxetine in the development of this condition. • Microscopic colitis is the inflammation of the colon, presenting with chronic watery diarrhea and only microscopically evident histological changes. • Microscopic Colitis has two subtypes: Collagenous and Lymphocytic that are differentiated by specific histological characteristics. • Vortioxetine is an anti-depressant of the Serotonin Modulator and Stimulator class that has many adverse effects among which is collagenous colitis as presented by this case.